This invention relates in general to respirators and in particular to a new and useful respirator mask having one or more sealed areas within the mask located within a surrounding peripheral seal with the wearer's face and a connecting line therein which extends outwardly to the surrounding air and which contains a flow indicating device.
A similar respirator mask is known from German AS 17 08 047. The known respirator mask has a double seal edge by which protection of the apparatus wearer from penetrating pollutants is achieved in that there is at least one connection between the mask interior and the space between the two seal edges through which exhalation air is conducted into this space. The space between the two seal edges is always filled with exhalation air. In case of possible leaks between the seal edges and the skin surface of the mask wearer, penetration of outside air into the interior of the mask is avoided. If ambient air can penetrate into the space between the seal edges, this air is flushed out with the next exhalation.
Such a respirator mask is suitable for use with compressed air equipment, as the gases flushed out as part of the exhalation air are harmless with respect to their composition and also do not constitute a limitation to the duration of use of the compressed air equipment. By the use of the known respirator mask in conjunction with the circulation respirator apparatus in positive pressure operation, the discharge of the exhalation air through the space between the seal edges into the open would, in the course of time, cause a loss of inert gas, so that the oxygen concentration in the respiratory system increases. Hence the oxygen concentration in the exhalation air which is breathed out of the sealed interstices into the open also increases. This results in an unrecognizable danger to the user of the apparatus if he is near an open flame. if, moreover, in the course of using the known respirator mask with a circulation respirator apparatus the seal edges would somehow loosen or become detached, again exhalation air with a high oxygen concentration would escape through a greater leak at the seam frame of the mask.